let a = {
    itemName: "s1",
    ids: [1, 2, 3]
};

/**
 * 输出:
 * ```
 * itemName
 * ids
 * ```
 */
for (let tmp in a) {
    console.log(tmp);
}

for (let tmp1 in a.ids) {
    console.log(tmp1);
}